General-purpose engines or power generators provided with a general-purpose engine include an analog hour meter or a digital hour meter, comprising for example a liquid crystal display or seven segment LEDs (Light Emitting Diode), that counts engine ignition pulses in order to indicate an integrated operating time of the engine that is important for purposes of maintenance including engine oil change. Such general-purpose engines or power generators also include display lights that indicate various operating states, such as a power generating state, overload, power generation control system error and oil warning.
Heretofore, many patent applications have been filed for techniques which display operating states for maintenance purposes on general-purpose engines or power generators having a general-purpose engine. For example, Japanese Patent Application Laid-Open Publication No. 2005-343191 (JP 2005-343191 A) discloses a motive power vehicle which includes a liquid crystal display section and warning lights provided on an instrument panel. Further, Japanese Patent Application Laid-Open Publication No. HEI-11-311149 (JP H11-311149 A) discloses an engine management apparatus which stores and displays operating states of an engine, such as an operating time at the time of generation of a warning. Furthermore, Japanese Patent Application Laid-Open Publication No. 2005-299532 OP 2005-299532 A) discloses an engine failure history display apparatus which displays a recorded failure history each time a predetermined push button is operated by a human operator or user and which erases a previously recorded failure history when an engine stop switch and the push button have been operated simultaneously by the user.
However, because it is necessary to provide an hour meter and/or a display device dedicated to displaying of a failure history in addition to the output, indication lights, application of the conventionally-known techniques to a compact product, such as a portable inerter-type power generator, would be disadvantageous in terms of cost reduction. Further, the conventionally-known techniques would limit the layout and design freedom of the general-purpose engine or power generator.
Further, if a dedicated diagnosis tool usually possessed by a service person is used, it may be possible to check desired information pertaining to an integrated operating time by reference to a memory of an inverter unit provided in the general-purpose engine. However, because the dedicated diagnosis tool must be used, cumbersome operation would be required. Therefore, there has been a demand for a technique for allowing a user to readily visually recognize an integrated operating time of the engine.